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June 2, 1916]
tions prevailing in the island, and at least not
better adapted than the species from which
they sprung. Or, in other words, that they
did not originate in advantageous response to
those local conditions. A large amount of facts
and considerations has been brought forward
by the author in order to justify this conclu-
These conclusions provide us with a strong
argument against the hypothesis of a slow and
gradual evolution by small and almost invisible
steps, and for the theory of their production
by mutations. In the rare cases of rapid dis-
persal of new species a better adaptation may
of course be assumed as one of the chief factors,
but on the average the dispersal is very slow
in the beginning, giving no argument in favor
of this view.
Furthermore these considerations lead to the
view that wide distribution and commonness
are chiefly dependent on age, and only rarely
on adaptation. In every family the genera
with the widest distribution may be considered
as the oldest, those with a smaller domain as
younger, and the local endemics as the young-
est of all. These principles will be used in sub-
sequent studies to draw pedigrees of families.
But the studies made by the author up to this
time go to show that nearly all families have
the same general type of distribution, that
evolution of forms is on the average indiffer-
ent, and that most of the so-called adaptations
are of no special advantage to their possessors.
Another argument relates to the possible
size of mutations. It is often assumed that
mutations must of necessity be small, consider-
ing that it seems probable that only one unit-
factor will be changed at a time. This con-
ception seems to the author to be an unneces-
sary handicap to the theory of mutation and
he proposes that it should be replaced by the
hypothesis that no specific change is too great
to appear in one mutation. The difference be-
tween endemic species of Ceylon and their
nearest allies is often very large, as may be
deduced from the fact that they are accepted
as well-marked Linnean species by such author-
ities, as Trimen and Hooker. But in many
cases they are even larger. For instance,
Coleus elongatus, which occurs only on the top
of Ritigala and here only in about a dozen of
individuals, differs so much from all other
Gdlei, that it may well be regarded as sub-
generically distinct. And for the 17 endemic
genera, which have only one species each, it
seems at least very probable that the whole
genus has arisen at a single step.
In concluding I might state that my own
studies on the production of new forms among
the (Enotheras have of late led me to the con-
clusion that mutations are in many cases of a
far more complicated nature than has been
assumed until now. Many of them, as for in-
stance the production of 0. ruhrinervis, 0.
nanella and 0. gigas, involve the simultaneous
change of two or more characters, in some
cases of quite a large number of unit-factors.
Why these changes should so regularly go to-
gether, we do not, as yet, know, but the fact
goes to increase the analogy between the ex-
perimental mutations of these plants and the
mutations in the wild condition of the Ceylon
Prom the facts adduced by Willis, and re-
viewed in this article, it seems obvious that
the parallelism of natural and experimental
mutations is a very close one.
Hugo de Vbies
electrical discharge between concen-
tric cylindrical electrodes
In operating vacuum tubes we invariably
use an induction coil or an electrostatic ma-
chine. The discharge in either case is never
quite steady and hence these methods of opera
tion do not lend themselves well to a critical
study of the growth of the cathode dark
spaces. A steady, and of course continuous,
discharge may be had if the current is drawn
from a high potential storage battery. Ordi-
narily it takes more cells than are available;
however, by a right choice of conditions a
rather extended study may be made with di-
rect current potentials of less than 1,000 volts.
The following experiments with concentric
cylindrical electrodes were performed recently
by the writer in class demonstration.
The discharge vessel consists of an ordinary
[N. S. Vol. XLIII. No. 1118
three-quart battery jar. A hole bored through
the bottom receives the evacuating tube, the
junction being made airtight with ordinary
sealing wax. The lip of the jar is ground flat
to receive the plate glass lid. The junction
here is made by means of the frequently used
half-and-half wax, beeswax and resin. This
wax because of its low melting point admits
of easy removal of the glass plate. The elec-
trodes are concentric cylinders and may well
be made of sheet aluminum — one electrode to
fit snugly the inner wall of the jar, and the
other mounted on a cylinder of glass tubing
about 1J inches in diameter, which in turn is
supported accurately concentric by sealing
wax from the bottom of the jar. Outside con-
nections to the electrodes are made by fine
bare copper wire run out through the waxed
joints. The assembled discharge vessel is
shown at a in Pig. 1.
The vessel may be exhausted by a Gaede
mercury or a Gaede piston pump and, if de-
sired, the vacuum carried farther by the use
of charcoal and liquid air, though the latter is
-not necessary. The potential employed by
the writer to produce the discharge was fur-
nished by a cabinet of high potential storage
cells of 1,000 volts.
Two methods of operating were employed.
In the first an adjustable water resistance is
connected in series with the cells and dis-
charge vessel as shown at b in Fig. 1. When
the vacuum is right a beautiful discharge will
make its appearance as patches of light on the
electrodes. These patches of light, when there
is considerable resistance in the circuit and
the vacuum is not very high, will be opposite
each other and the discharge, as a whole, will
wander about, sometimes swinging entirely
around, or at times travelling to the edges of
the electrodes, only to break away and move
to some other point. The movement of the
cathode glow (which is the smaller and hence
the brighter) is similar to that of the cathode
star over the surface of mercury in a mercury
vapor lamp. These areas grow as the vacuum
improves when ultimately the entire surface
of each electrode is covered. Or, with the
vacuum kept constant, the areas may be made
to increase in size by cutting out resistance.
Hence by improving the vacuum and at the
same time cutting out resistance the dis-
charge, if the inner cylinder is made cathode,
grows rapidly into a brilliant bull's-eye. The
appearance is very realistic, for if now resist-
ance is cut in, the dark space around the
cathode (as is evident after a moment's re-
flection) grows smaller, and vice versa. Its
outline is exceedingly sharp and perfectly
steady, and yet, though the discharge appears
very brilliant, the current required may not
exceed 20 milliamperes.
This form of discharge vessel offers an in-
teresting method for the study of the stria-
tions and their relative spacing with reference
to the impressed discharge potentials. These
effects are best shown when the vacuum is not
too high and the discharge potential is ad-
justed to give a patch on the cathode, which
June 2, 1916]
we will take as the inner cylinder, of about
one square centimeter in area. Under these
conditions the Faraday dark space should be
about 8 mm. in length, and the Crookes dark
space should be just visible between the vel-
vety cathode glow and the cathode electrode.
Another prerequisite is that the discharge
must not cling to the edge of the aluminum
electrodes, but should occupy some intermedi-
ate position as shown at 1 in a, Fig. 1. In this
position the characteristics of the discharge
are shown with exceeding clearness. If now
some additional resistance is cut in, the area
of the discharge will become less, the Fara-
day dark space will shorten, the positive col-
umn will move towards the cathode, and the
number of strise in it will increase, the extra
strias being, as it were, drawn out of the anode.
The configuration is perfectly steady except
that the discharge, as a whole, is liable to
wander. This transition may be continued by
a still further increase of the resistance in the
circuit, the dark space becoming ever shorter,
the positive column lengthening and at the
same time shrinking in area and the striae in-
creasing in number, all without loss of out-
line or brightness. Finally, the discharge will
cease. The various stages are suggested at 1,
2, 3 in h, Fig. 1.
In the second method the discharge vessel
with its commutator is placed in a derived
circuit (Fig. 2). This arrangement enables the
discharge potential to be continuously varied
over a wide range, and hence for a given
vacuum the relation between the length of the
dark space and the impressed voltage may be
exhibited. Again this arrangement enables
the minimum potential -to be readily deter-
mined that will maintain a discharge. As an
example, for a given vacuum with the resist-
ance AG equal to 1/3 that of AB the discharge
was observed to just pass, indicating that the
potential necessary was 330 volts.
Additional phases of the experiment will
suggest themselves to the operator.
Chas. T. Knipp
Laboratory op Physics,
University op Illinois,
March 4, 1916
UTAH ACADEMY OF SCIENCES
The ninth annual convention of the Utah Acad-
emy of Sciences was held in the chemistry lecture
room of the University of Utah. Three sessions
were held: one at eight p.m., Friday, April 7, one
at ten A.M., Saturday, April 8, and the closing ses-
sion at two p.m. of the same day. Dr. Harvey
Fletcher presided at all of the sessions.
Dr. E. G. Peterson, U. A. C, and Professor
Carl P. Eyring, B. Y. U., were elected to fellow-
ships in the academy. The following were elected
members: Professor George B. Caine, U. A. ft,
Dean Milton Bennion, U. U., Professor Newton
Miller, U. U., Professor A. L. Matthews, U. U.,
Dr. George S. Snoddy, U. U., Miss Hazel L.
Morse, East High School, Salt Lake City, C. Ar-
thur Smith, East High School, Salt Lake City, C.
Oren Wilson, East High School, Salt Lake City,
Professor Estes P. Taylor, U. A. ft, Dr. A. P.
Henderson, B. Y. U., and Edgar M. Ledyard, Salt
Captain Francis Marion Bishop, a companion of
Major Powell in his famous explorations of the
Uinta Mountains, was elected to honorary life
The following officers were elected for the en-
President — Dr. Frank Harris, U. A. ft, Logan.
First Vice-president — Dr. L. L. Daines, U. U.,
Salt Lake City.
Second Vice-president — Professor Carl F. Ey-
ring, B. Y. U., Provo.
Councillors — Dean J. L. Gibson, U. U., Dr. W.
E. Carroll, U. A. ft, W. D. Neal, Salt Lake City.
The following lectures and papers were pre-
' ' Industrial Eesearch in U. S. A., ' ' by Dr. Har-
vey Fletcher, B. Y. U.
"The Alkali Content of Certain Utah Soils," by
Dr. Frank S. Harris, U. A. C.
"The Agricultural College and Scientific Ee-
search," by Dr. E. G. Peterson, U. A. C.
"Selecting Holstein-Friesian Bulls by Perform-
ance," by Dr. W. E. Carroll, U. A. ft
"Peyote, an Indian Narcotic," by A. O. Gar-
rett, East High School, Salt Lake City.
' ' An Epidemic of Colds with Micrococcus catar-
rhalis as Causative Agents, ' ' by Dr. L. L.
Daines, U. U.
"The First Becorded Case of Babies in Utah,"
by Dr. L. L. Daines, U. U.
"Botulinus Poisoning from a Vegetable
Source, ' ' by Dr. L. L. Daines, U. U.
"Comparison of Methods of Treatment for